Prior art of possible relevance includes the following U.S. Pat. Nos. 1,041,721 issued Oct. 22, 1912 to Ball; 3,600,114 issued Aug. 17, 1971 to Dvorak et al; 4,178,143 issued Dec. 11, 1979 to Thelen et al; 4,383,805 issued May 17, 1983 to Teegarden et al; and 4,389,171 issued June 21, 1983 to Eber et al. In addition, Japanese patent publication No. 53-141913 may be of relevance.
As is well known, many devices such as electric motors consume large quantities of energy when they are being started up. And, of course, the higher the loading during start-up, the more energy that is required. In some cases, where the motor is permanently coupled to the load, in order to overcome loadings during start-up, oversized motors are employed. That is, motors larger than would be required to maintain the load during constant state running conditions are necessitated in order to start-up when loaded.
In other environments, compressors or pumps may serve as auxiliary devices connected to a prime mover whose principal purpose is to provide power to perform some work other than the driving of the compressor for the pump. A primary example in an air conditioning system in an automotive vehicle.
In order to conserve energy, electically operated clutches are frequently inserted in the drive train between the prime mover and the compressor or pump so as to engage the latter to the former only where there is a requirement for the operation of the pump or compressor to save energy. This approach, while satisfactory in achieving energy savings, includes the extra expense of the clutch which in turn takes away from the desirable simplicity of the system.
The present invention is directed to overcoming one or more of the above problems in an environment where the load or pump or compressor is a scroll type positive displacement apparatus.